Pennsylvania Gov. Tom Wolf rejected a congressional map that was redrawn by Republican legislators after the state Supreme Court found illegal partisan bias in the previous version. (Lisa Lake/Getty Images for Geisinger Symposium)

Pennsylvania Gov. Tom Wolf rejected a congressional map that was redrawn by Republican legislators after the state Supreme Court found illegal partisan bias in the previous version.

The old map was characterized by noticeably odd-shaped districts that cut across county and municipal boundaries in a way the court ruled gave an unfair bias toward Republicans.

Why was the new map rejected?

While the new map is more compact and true to city and county borders than the old one, the new map resulted in a similar Republican advantage.

“The analysis by my team shows that, like the 2011 map, the map submitted to my office by Republican leaders is still a gerrymander,” Wolf said. “Their map clearly seeks to benefit one political party, which is the essence of why the court found the current map to be unconstitutional.”

Democrats hold only five out of Pennsylvania's 18 seats after the 2016 elections, despite Democratic candidates winning roughly half of the state's popular vote. Analyses have indicated that Republicans would have won the exact same number of seats under the newly drawn maps.

Republicans deny gerrymandering

Pennsylvania Republicans claim the map was drawn without the aid of partisan data.

“Partisan data was not used in any form in the development of the proposed map,” said Drew Compton, general counsel to Pennsylvania’s state Senate Republicans, to The Washington Post. “The proposed map fully complies with all the metrics laid out by the plaintiff experts in the case as well as the tests set forth in the majority opinion by the Supreme Court of Pa.”

Now what?

Now that Wolf has rejected the Republicans’ map, The Washington Post reports that the Supreme Court will instruct an independent redistricting expert to draw a new map from scratch.

The court could also consider new proposals from Wolf or Pennsylvania lawmakers. It has promised to present a new, final congressional map by Feb. 19.